Nicotine -

Options

A. stimulates adrenal gland
B. is an alkaloid
C. is present in tobacco
D. all of these

Answer

**Step-by-Step Solution:**

1. **Understanding Nicotine:**
- Nicotine is classified as an alkaloid, which is an organic compound that contains at least one nitrogen atom. Alkaloids are naturally occurring substances often found in plants.

2. **Source of Nicotine:**
- Nicotine is primarily found in tobacco plants. It is one of the key components that contribute to the addictive nature of tobacco products.

3. **Physiological Effects:**
- Nicotine has significant effects on the human body. It stimulates the adrenal glands, leading to the release of hormones such as adrenaline (epinephrine) and noradrenaline (norepinephrine).

4. **Impact on Blood Pressure and Heart Rate:**
- The stimulation of the adrenal glands by nicotine results in an increase in blood pressure and heart rate. This is due to the action of the hormones released, which prepare the body for a 'fight or flight' response.

5. **Evaluating the Options:**
- Based on the information gathered, we can evaluate the options provided in the question.
- The correct answer must reflect that nicotine is an alkaloid, it is present in tobacco, and it stimulates the adrenal glands.

6. **Choosing the Right Answer:**
- The correct option is D: "All of these," as it encompasses all the characteristics of nicotine discussed: it is an alkaloid, it is present in tobacco, and it stimulates the adrenal glands.

**Final Answer:**
- The correct answer is D: All of these.

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